The present invention relates to a welding device for operating in exiguous spaces, in particular for butt-joint welding parts, e.g. tubes.
Some apparatuses are already known, of the type comprising a module equipped with all mechanical and electrical components adapted to rotate about the parts to be welded together.
Such module includes the mechanisms for moving the electric torch and those for advancing the filler-metal, are feed and control circuits as well as circuits for controlling the angular position of the torch. The welding operations can be remotely controlled by means of a programmer.
Usually, the module is divided into two parts so as to allow the mounting and withdrawal thereof with respect to the parts to be welded together.
Such apparatuses are perfectly suitable for welding great lengths of heavy tubes with diameters of at least 50 millimeters. However, they require a large free space in the immediate vicinity of the welding area.
There also exist apparatuses of smaller volumes, capable of being introduced into a limited space and permitting the butt-joint welding of parts without the use of a filler metal, in particular tubes with an outer diameter of at least about 5 millimeters.
Such apparatuses are in the form of a portable tool provided with an openable rotor capable of being mounted about the parts to be welded. The rotor is driven by a crown-gear which, in its turn, can be divided into two parts. An electric torch is placed inside one of the rotor jaws.
In view of the reduced thickness of the rotor, it is not possible to introduce a filler-metal pouring device or an auxiliary fluid, so that such apparatuses can exclusively be used for the metal-to-metal fusion welding of the parts involved.